Transistor and semiconductor device

• US 9,748,401 B2
• Filed: 11/19/2014
• Issued: 08/29/2017
• Est. Priority Date: 06/25/2010
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Tsubuku, Masashi, Inoue, Takayuki, Hiraishi, Suzunosuke, Kikuchi, Erumu, Godo, Hiromichi, Yoshitomi, Shuhei, Inoue, Koki, Miyanaga, Akiharu, Yamazaki, Shunpei
• Primary Examiner(s): Pham, Long
• Application Number:
  US14/547,285
• Publication Number:
  US 20150069393A1
• Time in Patent Office: 1,014 Days
• CPC Class Codes: H01L 29/408 with an insulating layer with a particular dielectric or electrostatic property, e.g. with static charges or for controlling trapped charges or moving ions, or with a plate acting on the insulator potential or the insulator charges, e.g. for controlling charges effect or potential distribution in the insulating layer, or with a semi-insulating layer contacting directly the semiconductor surface
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate

Abstract

Manufactured is a transistor including an oxide semiconductor layer, a source electrode layer and a drain electrode layer overlapping with part of the oxide semiconductor layer, a gate insulating layer overlapping with the oxide semiconductor layer, the source electrode layer, and the drain electrode layer, and a gate electrode overlapping with part of the oxide semiconductor layer with the gate insulating layer provided therebetween, wherein, after the oxide semiconductor layer which is to be a channel formation region is irradiated with light and the light irradiation is stopped, a relaxation time of carriers in photoresponse characteristics of the oxide semiconductor layer has at least two kinds of modes: τ₁ and τ₂, τ₁<τ₂ is satisfied, and τ₂ is 300 seconds or less. In addition, a semiconductor device including the transistor is manufactured.

Claims

1. A transistor comprising:

an insulating layer;

an oxide semiconductor layer to be a channel formation region over the insulating layer;

a source electrode layer and a drain electrode layer overlapping with a part of the oxide semiconductor layer;

a gate insulating layer overlapping with the oxide semiconductor layer, the source electrode layer, and the drain electrode layer; and

a gate electrode overlapping with a part of the oxide semiconductor layer with the gate insulating layer provided therebetween,

wherein a thickness of the insulating layer is larger than a thickness of the gate insulating layer, and

wherein the oxide semiconductor layer In, Zn, and Ga.

2. The transistor according to claim 1, wherein the transistor has a property that, after the oxide semiconductor layer is irradiated with light and the light is turned off, a relaxation time of carriers in photoresponse characteristics of the oxide semiconductor layer has at least two kinds of modes:

τ

₁ and τ

₂, τ

₁<

τ

₂ is satisfied, and τ

₂ is 300 seconds or less.

3. The transistor according to claim 2, wherein a light source of the light is a white LED.

4. The transistor according to claim 2, wherein the oxide semiconductor layer has a first trap level close to a conduction band and a second trap level close to a valence band.

5. The transistor according to claim 1, wherein the gate insulating layer contains one or more elements selected from constituent elements of the oxide semiconductor layer.

6. The transistor according to claim 1, wherein the insulating layer is a silicon nitride film, a silicon oxide film, a silicon nitride oxide film, a silicon oxynitride film, an aluminum oxide film, a gallium oxide film, or a gallium aluminum oxide film.

7. A semiconductor device comprising:

a transistor comprising;

an insulating layer;

an oxide semiconductor layer to be a channel formation region over the insulating layer;

a source electrode layer and a drain electrode layer overlapping with a part of the oxide semiconductor layer;

a gate insulating layer overlapping with the oxide semiconductor layer, the source electrode layer, and the drain electrode layer; and

a gate electrode overlapping with a part of the oxide semiconductor layer with the gate insulating layer provided therebetween,

wherein a thickness of the insulating layer is larger than a thickness of the gate insulating layer, and

wherein the oxide semiconductor layer comprises In, Zn, Ga.

8. The semiconductor device according to claim 7, wherein, after the oxide semiconductor layer is irradiated with light and the light is turned off, a relaxation time of carriers in photoresponse characteristics of the oxide semiconductor layer has at least two kinds of modes:

τ

₁ and τ

₂, τ

₁ <

τ

₂ is satisfied, and τ

₂ is 300 seconds or less.

9. The semiconductor device according to claim 8, wherein a light source of the light is a white LED.

10. The semiconductor device according to claim 8, wherein the oxide semiconductor layer has a first trap level close to a conduction band and a second trap level close to a valence band.

11. The semiconductor device according to claim 7, wherein the gate insulating layer contains one or more elements selected from constituent elements of the oxide semiconductor layer.

12. The semiconductor device according to claim 7, wherein the semiconductor device is applicable to an electronic device.

13. The semiconductor device according to claim 7, wherein the insulating layer is a silicon nitride film, a silicon oxide film, a silicon nitride oxide film, a silicon oxynitride film, an aluminum oxide film, a gallium oxide film, or a gallium aluminum oxide film.